scholarly journals Modification of Human Papillomavirus Minor Capsid Protein L2 by Sumoylation

2010 ◽  
Vol 84 (21) ◽  
pp. 11585-11589 ◽  
Author(s):  
Martina Bergant Marušič ◽  
Nina Mencin ◽  
Mia Ličen ◽  
Lawrence Banks ◽  
Helena Šterlinko Grm

ABSTRACT The human papillomavirus (HPV) minor capsid protein L2 plays important roles in the generation of infectious viral particles and in the initial steps of infection. Here we show that HPV-16 L2 protein is sumoylated at lysine 35 and that sumoylation affects its stability. Interestingly, the sumoylated form of L2 cannot bind to the major capsid protein L1, suggesting a mechanism by which capsid assembly may be modulated in an infected cell. Additionally, L2 appears to modulate the overall sumoylation status of the host cell. These observations indicate a complex interplay between the HPV L2 protein and the host sumoylation machinery.

2016 ◽  
Vol 90 (14) ◽  
pp. 6314-6325 ◽  
Author(s):  
Mathieu Boxus ◽  
Michel Fochesato ◽  
Agnès Miseur ◽  
Emmanuel Mertens ◽  
Najoua Dendouga ◽  
...  

ABSTRACTAt least 15 high-risk human papillomaviruses (HPVs) are linked to anogenital preneoplastic lesions and cancer. Currently, there are three licensed prophylactic HPV vaccines based on virus-like particles (VLPs) of the L1 major capsid protein from HPV-2, -4, or -9, including the AS04-adjuvanted HPV-16/18 L1 vaccine. The L2 minor capsid protein contains HPV-neutralizing epitopes that are well conserved across numerous high-risk HPVs. Therefore, the objective of our study was to assess the capacity to broaden vaccine-mediated protection using AS04-adjuvanted vaccines based on VLP chimeras of L1 with one or two L2 epitopes. Several chimeric VLPs were constructed by inserting L2 epitopes within the DE loop and/or C terminus of L1. Based on the shape, yield, size, and immunogenicity, one of seven chimeras was selected for further evaluation in mouse and rabbit challenge models. The chimeric VLP consisted of HPV-18 L1 with insertions of HPV-33 L2 (amino acid residues 17 to 36; L1 DE loop) and HPV-58 L2 (amino acid residues 56 to 75; L1 C terminus). This chimeric L1/L2 VLP vaccine induced persistent immune responses and protected against all of the different HPVs evaluated (HPV-6, -11, -16, -31, -35, -39, -45, -58, and -59 as pseudovirions or quasivirions) in both mouse and rabbit challenge models. The degree and breadth of protection in the rabbit were further enhanced when the chimeric L1/L2 VLP was formulated with the L1 VLPs from the HPV-16/18 L1 vaccine. Therefore, the novel HPV-18 L1/L2 chimeric VLP (alone or in combination with HPV-16 and HPV-18 L1 VLPs) formulated with AS04 has the potential to provide broad protective efficacy in human subjects.IMPORTANCEFrom evaluations in human papillomavirus (HPV) protection models in rabbits and mice, our study has identified a prophylactic vaccine with the potential to target a wide range of HPVs linked to anogenital cancer. The three currently licensed vaccines contain virus-like particles (VLPs) of the L1 major capsid protein from two, four, or nine different HPVs. Rather than increasing the diversity of L1 VLPs, this vaccine contains VLPs based on a recombinant chimera of two highly conserved neutralizing epitopes from the L2 capsid protein inserted into L1. Our study demonstrated that the chimeric L1/L2 VLP is an effective vehicle for displaying two different L2 epitopes and can be used in a quantity equivalent to what is used in the licensed vaccines. Hence, using the chimeric L1/L2 VLP may be a more cost-effective approach for vaccine formulation than adding different VLPs for each HPV.


2015 ◽  
Vol 89 (20) ◽  
pp. 10442-10452 ◽  
Author(s):  
Stephen DiGiuseppe ◽  
Timothy R. Keiffer ◽  
Malgorzata Bienkowska-Haba ◽  
Wioleta Luszczek ◽  
Lucile G. M. Guion ◽  
...  

ABSTRACTThe human papillomavirus (HPV) capsid is composed of the major capsid protein L1 and the minor capsid protein L2. During entry, the HPV capsid undergoes numerous conformational changes that result in endosomal uptake and subsequent trafficking of the L2 protein in complex with the viral DNA to thetrans-Golgi network. To facilitate this transport, the L2 protein harbors a number of putative motifs that, if capable of direct interaction, would interact with cytosolic host cell factors. These data imply that a portion of L2 becomes cytosolic during infection. Using a low concentration of digitonin to selectively permeabilize the plasma membrane of infected cells, we mapped the topography of the L2 protein during infection. We observed that epitopes within amino acid residues 64 to 81 and 163 to 170 and a C-terminal tag of HPV16 L2 are exposed on the cytosolic side of intracellular membranes, whereas an epitope within residues 20 to 38, which are upstream of a putative transmembrane region, is luminal. Corroborating these findings, we also found that L2 protein is sensitive to trypsin digestion during infection. These data demonstrate that the majority of the L2 protein becomes accessible on the cytosolic side of intracellular membranes in order to interact with cytosolic factors to facilitate vesicular trafficking.IMPORTANCEIn order to complete infectious entry, nonenveloped viruses have to pass cellular membranes. This is often achieved through the viral capsid protein associating with or integrating into intracellular membrane. Here, we determine the topography of HPV L2 protein in the endocytic vesicular compartment, suggesting that L2 becomes a transmembrane protein with a short luminal portion and with the majority facing the cytosolic side for interaction with host cell transport factors.


2003 ◽  
Vol 77 (21) ◽  
pp. 11625-11632 ◽  
Author(s):  
Joseph J. Carter ◽  
Greg C. Wipf ◽  
Sarah F. Benki ◽  
Neil D. Christensen ◽  
Denise A. Galloway

ABSTRACT To characterize epitopes on human papillomavirus (HPV) virus-like particles (VLPs), a panel of mutated HPV-16 VLPs was created. Each mutated VLP had residues substituted from HPV-31 or HPV-52 L1 sequences to the HPV-16 L1 backbone. Mutations were created on the HPV-31 and −52 L1 proteins to determine if HPV-16 type-specific recognition could be transferred. Correct folding of the mutated proteins was verified by resistance to trypsin digestion and by binding to one or more conformation-dependent monoclonal antibodies. Several of the antibodies tested were found to bind to regions already identified as being important for HPV VLP recognition (loops DE, EF, FG, and HI). Sequences at both ends of the long FG loop (amino acids 260 to 290) were required for both H16.V5 and H16.E70 reactivity. A new antibody-binding site was discovered on the C-terminal arm of L1 between positions 427 and 445. Recognition of these residues by the H16.U4 antibody suggests that this region is surface exposed and supports a recently proposed molecular model of HPV VLPs.


2019 ◽  
Vol 400 (4) ◽  
pp. 513-522 ◽  
Author(s):  
Bastian Breiner ◽  
Laura Preuss ◽  
Nora Roos ◽  
Marcel Conrady ◽  
Hauke Lilie ◽  
...  

Abstract The minor capsid protein L2 of papillomaviruses exhibits multiple functions during viral entry including membrane interaction. Information on the protein is scarce, because of its high tendency of aggregation. We determined suitable conditions to produce a functional human papillomavirus (HPV) 16 L2 protein and thereby provide the opportunity for extensive in vitro analysis with respect to structural and biochemical information on L2 proteins and mechanistic details in viral entry. We produced the L2 protein of high-risk HPV 16 in Escherichia coli as inclusion bodies and purified the protein under denaturing conditions. A successive buffer screen resulted in suitable conditions for the biophysical characterization of 16L2. Analytical ultracentrifugation of the refolded protein showed a homogenous monomeric species. Furthermore, refolded 16L2 shows secondary structure elements. The N-terminal region including the proposed transmembrane region of 16L2 shows alpha-helical characteristics. However, overall 16L2 appears largely unstructured. Refolded 16L2 is capable of binding to DNA indicating that the putative DNA-binding regions are accessible in refolded 16L2. Further the refolded protein interacts with liposomal membranes presumably via the proposed transmembrane region at neutral pH without structural changes. This indicates that 16L2 can initially interact with membranes via pre-existing structural features.


2015 ◽  
Vol 89 (7) ◽  
pp. 3910-3921 ◽  
Author(s):  
Christian D. S. Nelson ◽  
Luisa J. Ströh ◽  
Gretchen V. Gee ◽  
Bethany A. O'Hara ◽  
Thilo Stehle ◽  
...  

ABSTRACTJC polyomavirus (JCPyV) infection of immunocompromised individuals results in the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). The viral capsid of JCPyV is composed primarily of the major capsid protein virus protein 1 (VP1), and pentameric arrangement of VP1 monomers results in the formation of a pore at the 5-fold axis of symmetry. While the presence of this pore is conserved among polyomaviruses, its functional role in infection or assembly is unknown. Here, we investigate the role of the 5-fold pore in assembly and infection of JCPyV by generating a panel of mutant viruses containing amino acid substitutions of the residues lining this pore. Multicycle growth assays demonstrated that the fitness of all mutants was reduced compared to that of the wild-type virus. Bacterial expression of VP1 pentamers containing substitutions to residues lining the 5-fold pore did not affect pentamer assembly or prevent association with the VP2 minor capsid protein. The X-ray crystal structures of selected pore mutants contained subtle changes to the 5-fold pore, and no other changes to VP1 were observed. Pore mutant pseudoviruses were not deficient in assembly, packaging of the minor capsid proteins, or binding to cells or in transport to the host cell endoplasmic reticulum. Instead, these mutant viruses were unable to expose VP2 upon arrival to the endoplasmic reticulum, a step that is critical for infection. This study demonstrated that the 5-fold pore is an important structural feature of JCPyV and that minor modifications to this structure have significant impacts on infectious entry.IMPORTANCEJCPyV is an important human pathogen that causes a severe neurological disease in immunocompromised individuals. While the high-resolution X-ray structure of the major capsid protein of JCPyV has been solved, the importance of a major structural feature of the capsid, the 5-fold pore, remains poorly understood. This pore is conserved across polyomaviruses and suggests either that these viruses have limited structural plasticity in this region or that this pore is important in infection or assembly. Using a structure-guided mutational approach, we showed that modulation of this pore severely inhibits JCPyV infection. These mutants do not appear deficient in assembly or early steps in infectious entry and are instead reduced in their ability to expose a minor capsid protein in the host cell endoplasmic reticulum. Our work demonstrates that the 5-fold pore is an important structural feature for JCPyV.


2016 ◽  
Vol 90 (8) ◽  
pp. 4115-4126 ◽  
Author(s):  
Zhanwen Guan ◽  
Ling Zhong ◽  
Chunyan Li ◽  
Wenbi Wu ◽  
Meijin Yuan ◽  
...  

ABSTRACTBaculovirus DNAs are synthesized and inserted into preformed capsids to form nucleocapsids at a site in the infected cell nucleus, termed the virogenic stroma. Nucleocapsid assembly ofAutographa californicamultiple nucleopolyhedrovirus (AcMNPV) requires the major capsid protein VP39 and nine minor capsid proteins, including VP1054. However, how VP1054 participates in nucleocapsid assembly remains elusive. In this study, the VP1054-encoding gene (ac54) was deleted to generate theac54-knockout AcMNPV (vAc54KO). In vAc54KO-transfected cells, nucleocapsid assembly was disrupted, leading to the formation of abnormally elongated capsid structures. Interestingly, unlike cells transfected with AcMNPV mutants lacking other minor capsid proteins, in which capsid structures were distributed within the virogenic stroma,ac54ablation resulted in a distinctive location of capsid structures and VP39 at the periphery of the nucleus. The altered distribution pattern of capsid structures was also observed in cells transfected with AcMNPV lacking BV/ODV-C42 or in cytochalasind-treated AcMNPV-infected cells. BV/ODV-C42, along with PP78/83, has been shown to promote nuclear filamentous actin (F-actin) formation, which is another requisite for nucleocapsid assembly. Immunofluorescence using phalloidin indicated that the formation and distribution of nuclear F-actin were not affected byac54deletion. However, immunoelectron microscopy revealed that BV/ODV-C42, PP78/83, and 38K failed to integrate into capsid structures in the absence of VP1054, and immunoprecipitation further demonstrated that in transient expression assays, VP1054 interacted with BV/ODV-C42 and VP80 but not VP39. Our findings suggest that VP1054 plays an important role in the transport of capsid proteins to the nucleocapsid assembly site prior to the process of nucleocapsid assembly.IMPORTANCEBaculoviruses are large DNA viruses whose replication occurs within the host nucleus. The localization of capsids into the capsid assembly site requires virus-induced nuclear F-actin; the inhibition of nuclear F-actin formation results in the retention of capsid structures at the periphery of the nucleus. In this paper, we note that the minor capsid protein VP1054 is essential for the localization of capsid structures, the major capsid protein VP39, and the minor capsid protein 38K into the capsid assembly site. Moreover, VP1054 is crucial for correct targeting of the nuclear F-actin factors BV/ODV-C42 and PP78/83 for capsid maturation. However, the formation and distribution of nuclear F-actin are not affected by the lack of VP1054. We further reveal that VP1054 interacts with BV/ODV-C42 and a capsid transport-related protein, VP80. Taken together, our findings suggest that VP1054 plays a unique role in the pathway(s) for transport of capsid proteins.


2017 ◽  
Vol 91 (16) ◽  
Author(s):  
Stephen DiGiuseppe ◽  
Malgorzata Bienkowska-Haba ◽  
Lucile G. M. Guion ◽  
Timothy R. Keiffer ◽  
Martin Sapp

ABSTRACT During infectious entry, acidification within the endosome triggers uncoating of the human papillomavirus (HPV) capsid, whereupon host cyclophilins facilitate the release of most of the major capsid protein, L1, from the minor capsid protein L2 and the viral genome. The L2/DNA complex traffics to the trans-Golgi network (TGN). After the onset of mitosis, HPV-harboring transport vesicles bud from the TGN, followed by association with mitotic chromosomes. During this time, the HPV genome remains in a vesicular compartment until the nucleus has completely reformed. Recent data suggest that while most of L1 protein dissociates and is degraded in the endosome, some L1 protein remains associated with the viral genome. The L1 protein has DNA binding activity, and the L2 protein has multiple domains capable of interacting with L1 capsomeres. In this study, we report that some L1 protein traffics with L2 and viral genome to the nucleus. The accompanying L1 protein is mostly full length and retains conformation-dependent epitopes, which are recognized by neutralizing antibodies. Since more than one L1 molecule contributes to these epitopes and requires assembly into capsomeres, we propose that L1 protein is present in the form of pentamers. Furthermore, we provide evidence that the L1 protein interacts directly with viral DNA within the capsid. Based on our findings, we propose that the L1 protein, likely arranged as capsomeres, stabilizes the viral genome within the subviral complex during intracellular trafficking. IMPORTANCE After internalization, the nonenveloped human papillomavirus virion uncoats in the endosome, whereupon conformational changes result in a dissociation of a subset of the major capsid protein L1 from the minor capsid protein L2, which remains in complex with the viral DNA. Recent data suggest that some L1 protein may accompany the viral genome beyond the endosomal compartment. We demonstrate that conformationally intact L1 protein, likely still arranged as capsomeres, remains associated with the incoming viral genome throughout mitosis and transiently resides in the nucleus until after the viral DNA is released from the transport vesicle.


Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 539
Author(s):  
Laurits Fredsgaard ◽  
Louise Goksøyr ◽  
Susan Thrane ◽  
Kara-Lee Aves ◽  
Thor G. Theander ◽  
...  

Capsid virus-like particles (cVLPs) are used as molecular scaffolds to increase the immunogenicity of displayed antigens. Modular platforms have been developed whereby antigens are attached to the surface of pre-assembled cVLPs. However, it remains unknown to what extent the employed cVLP backbone and conjugation system may influence the immune response elicited against the displayed antigen. Here, we performed a head-to-head comparison of antigen-specific IgG responses elicited by modular cVLP-vaccines differing by their employed cVLP backbone or conjugation system, respectively. Covalent antigen conjugation (i.e., employing the SpyTag/SpyCatcher system) resulted in significantly higher antigen-specific IgG titers compared to when using affinity-based conjugation (i.e., using biotin/streptavidin). The cVLP backbone also influenced the antigen-specific IgG response. Specifically, vaccines based on the bacteriophage AP205 cVLP elicited significantly higher antigen-specific IgG compared to corresponding vaccines using the human papillomavirus major capsid protein (HPV L1) cVLP. In addition, the AP205 cVLP platform mediated induction of antigen-specific IgG with a different subclass profile (i.e., higher IgG2a and IgG2b) compared to HPV L1 cVLP. These results demonstrate that the cVLP backbone and conjugation system can individually affect the IgG response elicited against a displayed antigen. These data will aid the understanding and process of tailoring modular cVLP vaccines to achieve improved immune responses.


2019 ◽  
Vol 10 (2) ◽  
pp. 82-89
Author(s):  
Silvia Tri Widyaningtyas ◽  
Sofy Meilany ◽  
Budiman Bela

Latar belakang: Secara alamiah protein kapsid L1 Human Papillomavirus (HPV) tipe 16 dapat mengalami auto assembly untuk membentuk Viral like particle (VLP). Terkait dengan penelitian vaksin HPV, VLP dapat digunakan untuk berbagai keperluan seperti vaksin, pseudovirion atau SpyTag-Spycatcher. Penelitian ini ditujukan untuk mendapatkan plasmid rekombinan yang digunakan untuk produksi protein L1 HPV 16. Metode: Gen penyandi protein L1 HPV 16 diklona ke dalam vector pQE80L, suatu plasmid yang mengandung sistem ekspresi untuk prokariota. DNA penyandi HPV 16 L1 disisipkan pada situs restriksi BamHI dan Hind III plasmid pQE80L. Plasmid rekombinan yang mengandung gen L1 HPV 16dikonfirmasi menggunakan PCR dan analisis enzim restriksi. Lebih lanjut untuk memastikan bahwa gen rekombinan L1 HPV 16 dapat diekspresikan dalam prokariota, plasmid rekombinan ditransformasikan ke bakteri Escherichia coli BL21 (DE3). Bakteri diinduksi dengan Isopropyl β-D-1-thiogalactopyranoside (IPTG) dengan berbagai konsentrasi dan berbagai waktu inkubasi. Hasil: protein rekombinan L1, berat 56 kDa, telah berhasil diekspresikan dalam sistem prokariota. Protein rekombinan L1 dapat dimurnikan menggunakan TalonR dalam kondisi denaturasi. Kesimpulan: gen L1 HPV 16 telah dikloning ke dalam pQE80L dan berhasil diekspresikan dalam sistem prokariota. (Health Science Journal of Indonesia 2019;10(2):82-9) Kata kunci: L1, HPV 16, cervical cancer   Abstract Background: Naturally Human Papillomavirus (HPV) type 16 L1 capsid protein can auto assemble to form Viral like particles (VLP). Concerning to vaccine development for HPV, VLP can be used for a variety of needs such as a vaccine, pseudovirion or SpyTag-Spycatcher. In this study, to obtain a vector expression that can be used in the production of HPV L1 protein, we cloned gene coding HPV 16 L1 protein into pQE80L a plasmid contains an expression system for prokaryote. Methods: The DNA coding HPV 16 L1 was inserted at BamHI and Hind III restriction sites of pQE80L plasmid. The recombinant plasmid containing the HPV L1 gene was confirmed using PCR colony and enzyme restriction. Further to ensure the recombinant HPV 16 L1 gene could be expressed in a prokaryote, the recombinant plasmid was transformed into bacteria Escherichia coli BL21 (DE3). The bacteria were induced with IPTG with various concentrations and various incubation time. Result: L1 recombinant protein, 56 kDa in weight, has successfully been expressed in prokaryote system. L1 recombinant protein can be purified using TalonR under denaturing conditions. Conclusion: L1 HPV 16 gene has been cloned into pQE80L and successfully expressed in prokaryote system. (Health Science Journal of Indonesia 2019;10(2):82-9) Keywords: L1, HPV 16, cervical cancer


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